Association and surface properties of diblock copolymers of ethylene oxide and DL‐lactide in aqueous solution

Diblock copolymers of ethylene oxide and DL ‐lactide (E m L n copolymers) were prepared by sequential anionic polymerisation and characterised by gel permeation chromatography (GPC) and 13 C NMR. Their association and surface properties in aqueous solution were studied by surface tension and dynamic and static light scattering. Comparison of the critical micelle concentrations (cmc) and micelle association numbers ( N w ) of the E m L n copolymers with published values for oxyethylene/oxybutylene (E m B n ) copolymers indicated a slightly lower hydrophobicity for a lactide unit: i.e. L ≃ 0.75B. The temperature dependence of the cmc of copolymer E 42 L 12 was analysed to obtain a standard enthalpy of micellisation Δ mic H 0 ≈ 40 kJ · mol −1 .